module RSpec::Mocks::ArgumentMatchers

def array_including(*args)

object.should_receive(:message).with(array_including([1,2,3]))
object.should_receive(:message).with(array_including(1,2,3))

@example

Ignores duplicates and additional values
Matches an array that includes the specified items at least once. 
def array_including(*args)
  actually_an_array = Array === args.first && args.count == 1 ? args.first : args
  ArrayIncludingMatcher.new(actually_an_array)
end